2001 540i, 91k miles. Previous owner replaced radiator, tank, thermostat, and hoses within last 6k miles. He can't remember if his mech changed water pump (dumb if didn't) and can't find that work order. I've got a coolant leak, uses 3-4 ounces over a 1000 mile trip. Just enough that it leaves some spots on the floor mid-way back engine (dripping down through oil pan drain access). I'm presuming that the pump has started to go TU. Any way to check and make sure ?? I've changed small block Chev and Mopar pumps over the years and with those it's relatively easy to look down on the pulleys and see if you've got a drip. There is so much stuff under the 540's hood that my old eyes haven't spotted anything.

Questions ....... if replacing should I use OEM or is there a better choice ? Also, how much of a PITA is this to do ??

Thanks in advance, Vaughan

11-30-2010, 11:10 PM

lezonebay

I did it on my 840 and no big deal.

the pump impeller is metal not plastic (at least on my 97 840 was metal) and I did get an aftermarket - but also came with metal impeller and it was a quality made. Cost was about 110 usd a few years ago. I also recommend changing the rear coolant hoses. They can age the same as the front ones and nobody ever changes them so they break and leave you stranded.
if they did change the radiator and thermostat it would be really dumb not to change the water pump but you never know.

There is an aux water pump and a junction valve (heater valve ?) on the driver side, all could be at fault.

I changed the water pump on my 1997 540i a few months ago, it was actually really easy. I also changed the thermostat and all of the hoses since I had them off anyway. Did you check to see if there was any play in the bearings?'97 540i auto